WASHINGTON — Federal authorities warned Wednesday that recent intelligence indicates that Al Qaeda may be plotting a terrorist attack on the subway or on other transit systems in New York City during the holidays.
U.S. officials stressed that the information, gathered by the FBI, had not been corroborated and said there was no indication that the suspected plot had progressed beyond preliminary discussion among operatives linked to Al Qaeda.
The warning comes at a time when New York subways and other public transportation systems are jammed with holiday travelers -- a scenario that counter-terrorism officials have long considered an attractive target for Al Qaeda.
A classified intelligence bulletin describing the suspected plot was issued Tuesday by the FBI and the Department of Homeland Security and disseminated among state and local law enforcement agencies, including the New York Police Department, according to U.S. counter-terrorism officials.
The bulletin said the FBI had "received a plausible but unsubstantiated report indicating that Al Qaeda terrorists in late September may have discussed targeting transit systems in and around New York City," according to a senior U.S. counter-terrorism official, citing language from the document but speaking about it on condition of anonymity.
The bulletin went on to say that the discussions "reportedly involved the use of suicide bombers or explosives placed on subway/passenger rail systems."
U.S. officials declined to elaborate on the source of the intelligence except to say that it was collected by the FBI, which focuses most of its intelligence-gathering efforts inside the U.S. but also has a significant presence overseas.
Justice Department and U.S. counter-terrorism officials said that no arrests had been made in connection with the plot and that there was no indication that potential participants had entered the U.S.
FBI spokesman Bill Carter said the report was issued "as a routine matter" so that local law enforcement officials could make plans for the holiday season.
The FBI and other federal agencies were heavily criticized in the aftermath of the Sept. 11, 2001, terrorist attacks for failing to share intelligence with local authorities.
The bulletin issued Tuesday was part of a system put in place to push more raw intelligence to local agencies. Last week, a similar warning on threats to the ferry system in Seattle was issued, officials said.
